Anyone know of any bad experiences (false trips) when a large UPS (1200 VA) serving computers is connected to a circuit protected by an AFCI breaker? How about a small neon indicator lamp?
The kind of UPS I am interested in the effects from is the "dual conversion continuous online" type, that is always converting the input AC to an internal DC, paralleling with the internal battery through some control circuit, and then converting that DC back to near-sine-wave AC to supply its outlets.
They make AFCI breakers rated for 1200kVA? I don't think it's a requirement, though you'd likely have to have ground fault protection built into the switchgear serving it. I've seen some problems with harmonics from the UPS rectifier in a pair of 500kVA UPSs causing relays in the switchgear to go nuts (my kingdom for a PLC!), but installing input filter cabinets fixed it. There's no hard and fast rule, but I like to spec out UPSs with less than 13% THD if it's a significant % of the generator/building load. Some of the better 12-switch UPSs meet it inherently, but nearly all 6-switch rectifiers (VFD, UPS or otherwise) need to have an input filter or the THD is just ridiculous.
Edit: wait, 1200VA or 1200kVA? You threw me off when you said "large" instead of "desktop"!
